摘要:
Apparatus and methods to perform focused sampling of reservoir fluid are described. An example method couples a sampling probe to a subterranean formation and, while the sampling probe is coupled to the subterranean formation, varies a pumping ratio of at least two displacement units to reduce a contamination level of a formation flu id extracted via the sampling probe from the subterranean formation.
摘要:
A drill string caliper includes a mandrel configured to be coupled within a drill string. At least one laterally extensible arm is coupled to an exterior of the mandrel. A biasing device is configured to urge the at least one arm into contact with a wall of a wellbore. A sensor is configured to generate an output signal corresponding to a lateral extent of the at least one arm.
摘要:
A method and apparatus for measuring the pressure of a formation penetrated by a wellbore is provided. A downhole tool is positioned in the wellbore and a probe is extended therefrom into sealing engagement with the formation. A piston in the probe is retracted therein where by a cavity is defined for receiving a fluid from the formation. A pressure underbalance in the cavity draws fluid from the formation into the cavity. An oscillator may be used to fluctuate the flow of fluid into the cavity. A pressure gauge is used to measure the pressure of fluid in the cavity.
摘要:
A composition for use in an oil chamber of a tool includes a hydraulic oil; and a surfactant, wherein the surfactant is present at an amount sufficient to form micelles in the hydraulic oil. The composition may further include an amphiphilic copolymer. A method includes providing a hydraulic fluid composition comprising a hydraulic oil and a surfactant capable of forming micelles in the hydraulic oil; and filling a hydraulic chamber in the tool with the hydraulic fluid composition. The hydraulic fluid composition may further include an amphiphilic copolymer.
摘要:
A method for determining formation pressure at a depth region of formations surrounding a borehole, including: keeping track of the time since cessation of drilling at the depth region; deriving formation permeability at the depth region; causing wellbore pressure to vary periodically in time and determining, at the depth region, the periodic and non-periodic component of pressure measured in the formations; determining, using the time, the periodic component and the permeability, the formation pressure diffusivity and transmissibility and an estimate of the size of the pressure build-up zone around the wellbore at the depth region; determining, using the time, the formation pressure diffusivity and transmissibility, and the non-periodic component, the leak-off rate of the mudcake at the depth region; determining, using the leak-off rate, the pressure gradient at the depth region; and extrapolating, using the pressure gradient and the size of the build-up zone, to determine the formation pressure.
摘要:
Methods and apparatus to control a formation testing operation based on a mudcake leakage are disclosed. A disclosed example method for use with a downhole tool disposed in a wellbore comprises measuring a property of a mudcake layer at a first location in a wellbore, determining a value representative of an estimated leakage through the mudcake layer based on the property, and determining, based on the value, whether to continue a formation testing operation.
摘要:
Methods and apparatus to control a formation testing operation based on a mudcake leakage are disclosed. A disclosed example method for use with a downhole tool disposed in a wellbore comprises measuring a property of a mudcake layer at a first location in a wellbore, determining a value representative of an estimated leakage through the mudcake layer based on the property, and determining, based on the value, whether to continue a formation testing operation.
摘要:
The present invention provides an apparatus for use in perforating a well having a plurality of explosive charges. Each explosive charge is adapted to generate a perforation tunnel in the formation adjacent to the well. In one embodiment, explosive charges are oriented to create perforation tunnels that converge at a location within the formation in order to create a fracture initiation plane capable of mitigating or avoiding hydraulic fracturing complications.
摘要:
A composition for use in an oil chamber of a tool includes a hydraulic oil; and a surfactant, wherein the surfactant is present at an amount sufficient to form micelles in the hydraulic oil. The composition may further include an amphiphilic copolymer. A method includes providing a hydraulic fluid composition comprising a hydraulic oil and a surfactant capable of forming micelles in the hydraulic oil; and filling a hydraulic chamber in the tool with the hydraulic fluid composition. The hydraulic fluid composition may further include an amphiphilic copolymer.